George C. Pimentel Lecture: Accelerated Reactions in Microdroplets and Thin Films

Seminar | October 22 | 4-5 p.m. | 120 Latimer Hall

 Graham Cooks, Department of Chemistry, Purdue University

 College of Chemistry

Reactions in small droplets with a gaseous interface are accelerated by orders of magnitude, the increase in rate being inversely dependent on the size of the droplet [1]. Acceleration is driven by the decreased activation energy (due to partial solvation) required for reactions occurring at the solution/gas interface [2], as shown in experiments on levitated droplets [3]. Recent data show that reactions at the interface of microdroplets are much faster than those in the droplet bulk. The use of such reactions in chemical synthesis on the 100’s mg scale is demonstrated for C-C coupling and other reactions.[4] High throughput reaction screening has been automated so that chemical reactions, accelerated in DESI microdroplets, can be read at rates of some 6,000 unique reactions/hour so allowing high dimensional exploration of chemical reaction space.[5] To accomplish this, a DESI-MS system was integrated with instrumentation for automated robotic pipetting, transfer of arrays of samples and precision solvent delivery. Data from this automated system can assist in optimizing synthetic routes to drugs.[6]
[1] Müller, et al. Angew. Chem. Int. Ed. 51 (2012) 11832-11835
[2] Yan, et al. Angew. Chem. Int. Ed. 55 (2016) 12960-12972
[3] Li, et al. Chem. Eur. J. 24 (2018) 7349 – 7353
[4] Wei, et al Chem. Sci., 2018, 9, 7779 – 7786
[5] Wleklinski, et al. Chem. Sci. 9 (2018) 1647 – 1653
[6] Jaman, et al. Org. Process Res. Dev, (2019), DOI: 10.1021/acs.oprd.8b00387